The results of the Sodalis Nature Preserve bat census reveal both good and bad news.
There are nearly 44,000 more of the federally endangered Indiana bats living at the preserve since the last census count in 2015, the February census showed, but white nose syndrome, the likely culprit, has dramatically reduced the other species of bats in the same two-year period.
The numbers of the gray bat, also federally endangered, dropped from 570 to 31, and the threatened northern long-eared bat went from having 83 living at the preserve to none. Three other species saw drops of 50 percent or more in numbers, as well as bats that were unidentified as belonging to a particular group.
“We have known since the previous census that white nose syndrome was at the preserve,” Missouri Bat Census Director Kirsten Alvey-Mudd said.
The disease, first documented about 2007, is a fungus found on the muzzles and wings of hibernating bats, U.S. Geological Survey research shows. It has a 90 percent to 100 percent mortality rate on affected bats.
“The northern long-eared bat has been hardest hit by white nose syndrome,” Alvey-Mudd said. “It’s sad. We’ve only seen seven northern long-eared bats in the entire state this year.”
As for the gray bat, Alvey-Mudd is not as concerned about its population numbers.
“We’ve had a mild winter, and warm weather causes them to emerge from hibernation to seek out a colder environment,” she said. “This could be the reason for the fluctuation in numbers. Across the state, their population numbers are stable.”
Hannibal has one-third of the world’s population of Indiana bats, and to see the endangered species increase in size is encouraging to Alvey-Mudd.
“We’re happy in regard to that. Gating that area has made it much more conducive for them to return and raise their young,” she said.
In February, about 40 people took part in the survey. They counted hibernating bats in the former limestone mines for about four hours. Conservation officials take a census of bats every two years.
— By Ashley Szatala